Si diffusion in p-GaN

The characteristics of p-type Mg-doped GaN films diffused with Si are studied. N-type conductivity is achieved, and the carrier mobility of diffused GaN is 90–150 cm2 V−1 s−1, higher than that of p-GaN but less than that of epitaxially grown n-GaN. The Mg acceptor states could become deep compensating defects, and the compensation ratio NA/ND is 0.3, 0.45, 0.6, and 0.75 for 800, 900, 1000, and 1100 °C diffused GaN, respectively. The carrier transport may be dominated by electron hopping through these deep compensating centers or through diffusion. The results of temperature-dependent carrier concentration indicate that thermal annealing may induce defects at the surface, leading to an additional activation energy Ed∼10 meV in the 200–500 K region in diffused GaN.